A goal from Longstaff on his Premier League debut gave Steve Bruce’s side a 1-0 win over Manchester United at St James’s Park before the international break.
The 19-year-old is out of contract next summer, and the club want to secure the midfielder – who could face Chelsea at Stamford Bridge on Saturday – on a long-term deal.
Speaking last week, Longstaff said: “Obviously, I want to stay at Newcastle. But the biggest thing for me is just to carry on playing well, and that will take care of itself.”
A new contract for Longstaff’s older sibling Sean has been on the agenda at St James’s Park since March, when an impressive run in the team, then managed by Rafa Benitez, was brought to an end by a season-ending knee injury.
The 21-year-old had signed a new contract late last year before he made his Premier League debut. The deal keeps Longstaff at the club until 2022.
Longstaff was a target for Man United in the summer. The club was willing to pay £35million for the midfielder, but Newcastle made it clear that he was not for sale.
There have been discussions on a new deal which would reflect Longstaff's new status as a first-team starter.
However, there has been little progress on a new contract for Longstaff – who was a loan target for Rangers last year – over the past couple of months.
Speaking earlier this month, Bruce said: “There’s no problem there, contract-wise. The thing for him now is forget contracts, forget his knee injury, forget Man Utd – it’s about playing well for us now and getting back to playing like we know he’s capable (of playing).”
Bruce – who spoke about Longstaff’s importance to the team after his appointment as head coach in the summer – may be able broker a compromise deal.
Benitez and Alan Pardew, as incoming United managers, were able to resolve long-running contract disputes with Rolando Aarons and Steven Taylor respectively.
Longstaff, for his part, is focused on helping the team.